Good question. I heard the earlier ones were a bit fragile. I've only ever owned a few TA03 diffs, because they're tough as nails. Just rebuild every few years and you're good. I have heard of some breaking the adjuster nut, however.
I missed having an actual diff in my car so much - we all went to the fluid filled diffs here, with 500,000 - 1.5M wt silicone - that I've stuffed a fairly loose TA03 diff back in there. I don't win races (and I wouldn't anyway) but my car is an absolute joy to drive.